Osteoporosis - Page 2

The Patient History will identify individuals with high risk behaviors. Patients who have a prior osteoporotic fracture, long-term glucocorticoid use, and organ failure or transplant present the greatest risk. The risk of falls is high among the elderly, and one third of community-dwelling and one half of nursing home residents fall each year.[i]   Two to 5 % of falls result in fractures. Clinical risk categories and risk for falls are summarized in Lash.[ii] Slide08 Slide09

As part of the Patient History, an Osteoporosis Risk Questionnaire can be completed while the patient is in the waiting room and reviewed by a medical assistant for completeness. This record should become part of the patient’s record and can be scanned into electronic charts to  use as a baseline in risk assessment. High risk behaviors include smoking, low body weight, personal history of fracture as an adult, and history of a fracture in a first-degree relative (mother, father, or sibling).[iii]   Sedentary life style and excessive alcohol add to risk profile.

Physical examination, beginning with appearance, can provide cues for further testing. An appearance “older than stated age,” obesity, or weight under 127 pounds,  decrease in height,  a thoracic “dowager’s hump,” and unequal leg length require follow-up. Current recommendations for BMD include all women older than 65 years, postmenopausal women younger than 65 years who have risk factors for osteoporosis, women at risk for osteoporosis who are in the menopausal transition, women who are discontinuing estrogen therapy,  Slide10 and men or 70 years of age. The International society for Clinical Densitometry (ISCD) provides the most comprehensive guidelines for recommending BMD. [iv] 

Measurement of bone density and laboratory tests provide additional diagnostic data for the initiation of treatment. The “gold standard technology” for measuring bone mineral density (BMD) is dual-energy absorptiometry (DXA/DEXA).  Because BMD and bone strength are strongly correlated, DXA testing provides accuracy and low radiation risk. DXA uses photon beams of two different energy levels of ionizing radiation to measure bone mineral content in grams and bone area in square centimeters which is computed to calculate BMD as grams per square centimeter. This is reported as a T-score or a Z- score which represents the standard deviation between the patient’s BMD and the mean BMD of a young adult female.  T-scores are used in diagnostic criteria for older adults, whereas Z-scores are used for pediatric and adolescent populations, and in suspected secondary osteoporosis in young adults. Z-scores provided an age-matched reference population.[v]   International Society for Clinical Densitometry  Official Positions state that DXA studies routinely measure the non-dominant hip and the lumbar spine, unless there has been a fracture in the area, or metal parts in that leg. In patients who are excessively obese, have hyperparathyroidism, or otherwise could not have a hip and spinal DXA, the non dominant forearm is used. The lateral spine image with DXA (vertebral fracture assessment) can also diagnose unrecognized fractures of the vertebra with less radiation, more patient convenience, and at a lower cost than standard spinal radiographs.

Treatment guides depend upon the professional society that has authored guidelines based on T-score, clinical risk assessment, and  populations. The National Osteoporosis Foundation (NOF) is probably the most-used clinical practice guideline in the U.S.  and recommends treating postmenopausal Caucasian women when the T-score is less that -2.0 with no risk factors, and T-score less than -1.5 when risk factors are present. Currently, due to a lack of other specific  criteria, the same diagnostic criteria is applied to men. [vi] The WHO Fracture Risk Assessment Tool (FRAX) uses BMD information in determining a 10 year fracture risk.[vii]

Some DXA results are reported in Z-scores which are used for premenopausal women, children, and men younger than 50 years. If a Z-score is used in these patients, a value less than -2.0 is defined as “less than expected for age.”

When possible, follow-up DXA should be performed on the same machine a minimum of 2 years apart (unless otherwise indicated by clinical and laboratory profile). Repeated DXA on the same equipment increases the precision and reproducibility, and a 2 year time lapse provides more meaningful information on bone loss than annual tests.

Quantitative ultrasound (QUS), usually of the heel or other peripheral skeletal sites is most useful as a health education tool or a screening method to decide referrals for a DXA. These small, portable devices do not use radiation and are less expensive than DXA; however, the overall value of QUS is not confirmed by research.  T-scores provided by GUS are not equivalent to DXA T-scores and should not be used for diagnostic purposes.

Biochemical bone markers of bone turnover in serum or urine are used to assess the effectiveness of anti-resoptive therapy. This test is not a reliable predictor of BMD, and is not a substitute or an enhancement of DXA.[viii]  In fact, bone markers, such as those used in research settings, may create an independent risk for fractures in older women.

Secondary osteoporosis  Although most cases of osteoporosis are age-related, PMO, or idiopathic,  several secondary causes are treatable, such as hypogonadism, hyperparathyroidism,  and malabsorption syndrome. Other conditions are important to diagnose, such as renal failure and multiple myeloma.  Approximately 50% of men with osteoporosis have a secondary cause and warrant investigation.[ix]

Laboratory tests

All patients should be considered for laboratory tests that include complete blood count, serum calcium, alkaline phosphatase, renal function, liver function, thyroid stimulating hormone, and thyrotropin. Estradiol and follicle-stimulating hormone should be added in cases of amenorrhea unrelated to menopause, pregnancy, or polycystic ovary syndrome.  Slide09

  Total testosterone and 25-hydroxyvitamin D  are included in tests on men.

Fink and others (2006) found that men with testosterone or estradiol deficiency were more likely to have osteoporosis. Conversely, older men with osteoporosis were more likely to have total testosterone or estradiol deficiency. Moreover, older men with total testosterone deficiency were more likely to experience subsequent rapid bone loss.[x] BMD testing of older men with sex steroid deficiency is warranted to identify those with osteoporosis who potentially may benefit from bisphosphonate therapy.   Clinician awareness of osteoporosis in these men is relevant because bisphosphonate treatment may reduce their subsequent risk of fractures.[xi]  While study data suggest that older men with osteoporosis have an increased prevalence of total testosterone or estradiol deficiency, it is uncertain whether measurement of sex steroid levels in osteoporotic men provides additional information that would change their clinical management. By virtue of being osteoporotic, these men may already be candidates for bisphosphonate therapy.  Slide11

Clinical situations might indicate additional tests for urinary calcium, 25-hydroxyvitamin D, 24-hour urine-free cortisol, or other tests indicated for malignancy.

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